diff --git a/esphome/components/web_server_idf/utils.cpp b/esphome/components/web_server_idf/utils.cpp
index 81ae626277f..d9c43bd6c7a 100644
--- a/esphome/components/web_server_idf/utils.cpp
+++ b/esphome/components/web_server_idf/utils.cpp
@@ -1,17 +1,13 @@
 #ifdef USE_ESP32
-#include <memory>
 #include <cstring>
 #include <cctype>
 #include "esphome/core/helpers.h"
-#include "esphome/core/log.h"
 #include "http_parser.h"
 
 #include "utils.h"
 
 namespace esphome::web_server_idf {
 
-static const char *const TAG = "web_server_idf_utils";
-
 size_t url_decode(char *str) {
   char *start = str;
   char *ptr = str, buf;
@@ -54,38 +50,29 @@ optional<std::string> request_get_header(httpd_req_t *req, const char *name) {
   return {str};
 }
 
-optional<std::string> request_get_url_query(httpd_req_t *req) {
-  auto len = httpd_req_get_url_query_len(req);
-  if (len == 0) {
-    return {};
-  }
-
-  std::string str;
-  str.resize(len);
-
-  auto res = httpd_req_get_url_query_str(req, &str[0], len + 1);
-  if (res != ESP_OK) {
-    ESP_LOGW(TAG, "Can't get query for request: %s", esp_err_to_name(res));
-    return {};
-  }
-
-  return {str};
-}
-
 optional<std::string> query_key_value(const char *query_url, size_t query_len, const char *key) {
   if (query_url == nullptr || query_len == 0) {
     return {};
   }
 
-  // Use stack buffer for typical query strings, heap fallback for large ones
-  SmallBufferWithHeapFallback<256, char> val(query_len);
-
-  if (httpd_query_key_value(query_url, key, val.get(), query_len) != ESP_OK) {
+  char val[CONFIG_HTTPD_MAX_URI_LEN + 1];
+  if (httpd_query_key_value(query_url, key, val, query_len) != ESP_OK) {
     return {};
   }
 
-  url_decode(val.get());
-  return {val.get()};
+  url_decode(val);
+  return {val};
+}
+
+bool query_has_key(const char *query_url, size_t query_len, const char *key) {
+  if (query_url == nullptr || query_len == 0) {
+    return false;
+  }
+  // Minimal buffer — we only care if the key exists, not the value
+  char buf[1];
+  // httpd_query_key_value returns ESP_OK if key found (even if buffer too small for value),
+  // ESP_ERR_NOT_FOUND if key absent
+  return httpd_query_key_value(query_url, key, buf, sizeof(buf)) != ESP_ERR_NOT_FOUND;
 }
 
 // Helper function for case-insensitive string region comparison
diff --git a/esphome/components/web_server_idf/utils.h b/esphome/components/web_server_idf/utils.h
index 87635c04584..027a2f7b6cb 100644
--- a/esphome/components/web_server_idf/utils.h
+++ b/esphome/components/web_server_idf/utils.h
@@ -13,11 +13,8 @@ size_t url_decode(char *str);
 
 bool request_has_header(httpd_req_t *req, const char *name);
 optional<std::string> request_get_header(httpd_req_t *req, const char *name);
-optional<std::string> request_get_url_query(httpd_req_t *req);
 optional<std::string> query_key_value(const char *query_url, size_t query_len, const char *key);
-inline optional<std::string> query_key_value(const std::string &query_url, const std::string &key) {
-  return query_key_value(query_url.c_str(), query_url.size(), key.c_str());
-}
+bool query_has_key(const char *query_url, size_t query_len, const char *key);
 
 // Helper function for case-insensitive character comparison
 inline bool char_equals_ci(char a, char b) { return ::tolower(a) == ::tolower(b); }
diff --git a/esphome/components/web_server_idf/web_server_idf.cpp b/esphome/components/web_server_idf/web_server_idf.cpp
index ddc65e44ad5..44ed8f3e8a4 100644
--- a/esphome/components/web_server_idf/web_server_idf.cpp
+++ b/esphome/components/web_server_idf/web_server_idf.cpp
@@ -393,13 +393,7 @@ AsyncWebParameter *AsyncWebServerRequest::getParam(const char *name) {
   }
 
   // Look up value from query strings
-  optional<std::string> val = query_key_value(this->post_query_.c_str(), this->post_query_.size(), name);
-  if (!val.has_value()) {
-    auto url_query = request_get_url_query(*this);
-    if (url_query.has_value()) {
-      val = query_key_value(url_query.value().c_str(), url_query.value().size(), name);
-    }
-  }
+  auto val = this->find_query_value_(name);
 
   // Don't cache misses to avoid wasting memory when handlers check for
   // optional parameters that don't exist in the request
@@ -412,19 +406,37 @@ AsyncWebParameter *AsyncWebServerRequest::getParam(const char *name) {
   return param;
 }
 
-optional<std::string> AsyncWebServerRequest::find_query_value_(const char *name) const {
-  auto val = query_key_value(this->post_query_.c_str(), this->post_query_.size(), name);
-  if (val.has_value()) {
-    return val;
+/// Search post_query then URL query with a callback.
+/// Returns first truthy result, or value-initialized default.
+/// Uses stack buffer for URL query to avoid heap allocation.
+template<typename Func>
+static auto search_query_sources(httpd_req_t *req, const std::string &post_query, const char *name, Func func)
+    -> decltype(func(nullptr, size_t{0}, name)) {
+  if (!post_query.empty()) {
+    auto result = func(post_query.c_str(), post_query.size(), name);
+    if (result) {
+      return result;
+    }
   }
-  auto url_query = request_get_url_query(*this);
-  if (url_query.has_value()) {
-    return query_key_value(url_query.value().c_str(), url_query.value().size(), name);
+  auto len = httpd_req_get_url_query_len(req);
+  if (len == 0) {
+    return {};
   }
-  return {};
+  char buf[AsyncWebServerRequest::URL_BUF_SIZE];
+  if (httpd_req_get_url_query_str(req, buf, len + 1) != ESP_OK) {
+    return {};
+  }
+  return func(buf, len, name);
 }
 
-bool AsyncWebServerRequest::hasArg(const char *name) { return this->find_query_value_(name).has_value(); }
+optional<std::string> AsyncWebServerRequest::find_query_value_(const char *name) const {
+  return search_query_sources(this->req_, this->post_query_, name,
+                              [](const char *q, size_t len, const char *k) { return query_key_value(q, len, k); });
+}
+
+bool AsyncWebServerRequest::hasArg(const char *name) {
+  return search_query_sources(this->req_, this->post_query_, name, query_has_key);
+}
 
 std::string AsyncWebServerRequest::arg(const char *name) {
   auto val = this->find_query_value_(name);